Field of the Invention
Embodiments of the present invention relate generally to network switches and, more specifically, to automatic configuration of a network switch in a multi-chassis link aggregation group.
Description of the Related Art
In Ethernet switch systems, a conventional link aggregation group (LAG) oftentimes represents multiple links connected to a single physical switch. A common media access control (MAC) address serves as the address of the switch on all of the aggregated links, which allows traffic to be sent to the switch on any of the aggregated links at the same MAC address. Thus, the aggregated links appear as a single link to the transmitting devices, such as server machines, where the transmitting devices do not know that there are multiple links connected via the single MAC address. One advantage of a conventional LAG is that, if one of the aggregated links fails, the other aggregated links remain active, which preserves a portion of the original bandwidth provided by the aggregated links. However, one disadvantage of a conventional LAG is that, if the physical switch fails, all of the aggregated links are disconnected, and all of the original bandwidth provided by the aggregated links is lost.
To remedy this problem, a pair of physical switches (i.e., two different physical devices, or chassis) replaces the single switch, and a multi-chassis link aggregation group (MLAG) represents multiple links connected to this pair of physical switches. In the case of an MLAG system, each transmitting device has two links to the pair of switches, with one link connected to each switch. Similar to a conventional LAG, the same common MAC address serves as the address of either switch on all of the aggregated links. Thus, the aggregated links to either switch appear as a single link to the transmitting devices, such as server machines, where the transmitting devices do not know that there are multiple links or multiple switches connected via the single MAC address. One advantage of an MLAG system similar to a conventional LAG is that, if one of the aggregated links fails, the other aggregated links remain active, which preserves a portion of the original bandwidth provided by the aggregated links. One additional advantage of an MLAG system over a conventional LAG is that, if a physical switch (or chassis) fails, there is still one other physical switch remaining active, which preserves a portion of the original bandwidth provided by the aggregated links. Thus, in contrast to a traditional LAG, where a physical switch failure causes all of the original bandwidth provided by the aggregated links to be lost, in an MLAG system, a physical switch failure preserves some of the original bandwidth.
When establishing an MLAG system, the switches and links must be configured, for instance, by entering commands through a command line interface (CLI) on a computing device connected to the MLAG system. A first configuration step is to configure the common interface between the two switches (e.g., a first switch and a second switch). This first configuration step requires entering at a minimum five commands entered for each of the first and second switches, including commands to enable MLAG communication between the switches, commands setting a system_identifier as the common MAC address for both switches, and commands to establish an inter peer link (IPL) between the first and second switches. A second configuration step is to configure all connections between the switches and downlink transmitting devices, such as server machines. This second configuration step requires entering at a minimum four commands for each link between each of the first and second switches and each downlink transmitting device. Thus, for each downlink transmitting device, these four commands must be issued twice, once for the first switch, and once for the second switch.
One drawback to the above approach is that a large number of commands must be entered through the CLI in order to configure the MLAG system. In a typical implementation, each of the first and second switches may include a large number (e.g., up to 56 or more) of downlink ports (or links to downlink transmitting devices). In this implementation, configuring the MLAG system requires manually entering hundreds of commands through the CLI, which is time-consuming and tedious, and is thus prone to human-error. Further, whenever there is a change in the MLAG system, such as a change of a cable or a change of one of the physical switches (or chassis), many or all of the configuration commands must be entered again.
As the foregoing illustrates, what is needed in the art is a more effective approach for configuring MLAG systems.